On Wed, Mar 4, 2026 at 2:49 PM Radosav Krunic
<[email protected]> wrote:
>
> This patch addresses a regression introduced in r8-568-gf9f69dd651b2f1
> (i.e., refactoring ivopts pass) for target mips-r6-linux-gnu. It
> corrects the complexity calculation in ivopts. The fix involves
> complexity computation reordering and proper invariant variables
> handling in address expressions. These changes align with the approach
> used before r8-568-gf9f69dd651b2f1 (e.g., in parent commit c2b64ce). The
> improved complexity calculations ensure better candidate selection and
> reduced code size, particularly for RISC CPUs.
>
> Signed-off-by: Radosav Krunic <[email protected]>
> Signed-off-by: Aleksandar Rakic <[email protected]>
> Signed-off-by: Jovan Dmitrovic <[email protected]>
Please state how you tested this patch.
> gcc/ChangeLog:
>
> * tree-ssa-loop-ivopts.cc (get_address_cost): Fixed
> complexity calculation.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/mips/bug_tree-optimization_109429.c: New test.
> ---
> .../mips/bug_tree-optimization_109429.c | 24 +++++++++
> gcc/tree-ssa-loop-ivopts.cc | 54 +++++++++----------
> 2 files changed, 50 insertions(+), 28 deletions(-)
> create mode 100644
> gcc/testsuite/gcc.target/mips/bug_tree-optimization_109429.c
>
> diff --git a/gcc/testsuite/gcc.target/mips/bug_tree-optimization_109429.c
> b/gcc/testsuite/gcc.target/mips/bug_tree-optimization_109429.c
> new file mode 100644
> index 00000000000..96a62278fcd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/mips/bug_tree-optimization_109429.c
> @@ -0,0 +1,24 @@
> +/* { dg-do compile} */
> +/* { dg-skip-if "" { *-*-* } { "*" } { "-O2" } } */
> +/* { dg-options "-march=mips64r6 -mabi=64" } */
> +
> +static void daxpy (float *vector1, float *vector2, int n, float fp_const)
> +{
> + for (int i = 0; i < n; ++i)
> + vector1[i] += fp_const * vector2[i];
> +}
> +
> +void dgefa (float *vector, int m, int n, int l)
> +{
> + for (int i = 0; i < n - 1; ++i)
> + {
> + for (int j = i + 1; j < n; ++j)
> + {
> + float t = vector[m * j + l];
> + daxpy (&vector[m * i + i + 1],
> + &vector[m * j + i + 1], n - (i + 1), t);
> + }
> + }
> +}
> +
> +/* { dg-final { scan-assembler
> "\\.L6:\\n\\tlwc1\t\\\$f1,0\\\(\\\$7\\\)\\n\tdaddiu\t\\\$2,\\\$2,4\\n\tlwc1\t\\\$f0,-4\\\(\\\$2\\\)"
> } } */
> diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc
> index 6ecf5bef7b4..0df365671ef 100644
> --- a/gcc/tree-ssa-loop-ivopts.cc
> +++ b/gcc/tree-ssa-loop-ivopts.cc
> @@ -4695,38 +4695,35 @@ get_address_cost (struct ivopts_data *data, struct
> iv_use *use,
> if (!ok_with_ratio_p)
> parts.step = NULL_TREE;
> }
> - if (ok_with_ratio_p || ok_without_ratio_p)
> + if (!(ok_with_ratio_p || ok_without_ratio_p))
> + parts.index = NULL_TREE;
> + if (maybe_ne (aff_inv->offset, 0))
> {
> - if (maybe_ne (aff_inv->offset, 0))
> - {
> - parts.offset = wide_int_to_tree (sizetype, aff_inv->offset);
> - /* Addressing mode "base + index [<< scale] + offset". */
> - if (!valid_mem_ref_p (mem_mode, as, &parts, code))
> - parts.offset = NULL_TREE;
> - else
> - aff_inv->offset = 0;
> - }
> + parts.offset = wide_int_to_tree (sizetype, aff_inv->offset);
> + /* Addressing mode "base[+ index[<< scale]] + offset". */
> + if (!valid_mem_ref_p (mem_mode, as, &parts, code))
> + parts.offset = NULL_TREE;
> + else
> + aff_inv->offset = 0;
> + }
>
> - move_fixed_address_to_symbol (&parts, aff_inv);
> - /* Base is fixed address and is moved to symbol part. */
> - if (parts.symbol != NULL_TREE && aff_combination_zero_p (aff_inv))
> - parts.base = NULL_TREE;
> + move_fixed_address_to_symbol (&parts, aff_inv);
> + /* Base is fixed address and is moved to symbol part. */
> + if (parts.symbol != NULL_TREE && aff_combination_zero_p (aff_inv))
> + parts.base = NULL_TREE;
>
> - /* Addressing mode "symbol + base + index [<< scale] [+ offset]".
> */
> - if (parts.symbol != NULL_TREE
> - && !valid_mem_ref_p (mem_mode, as, &parts, code))
> - {
> - aff_combination_add_elt (aff_inv, parts.symbol, 1);
> - parts.symbol = NULL_TREE;
> - /* Reset SIMPLE_INV since symbol address needs to be computed
> - outside of address expression in this case. */
> - simple_inv = false;
> - /* Symbol part is moved back to base part, it can't be NULL. */
> - parts.base = integer_one_node;
> - }
> + /* Addressing mode "symbol + base[+ index[<< scale]] [+ offset]". */
> + if (parts.symbol != NULL_TREE
> + && !valid_mem_ref_p (mem_mode, as, &parts, code))
> + {
> + aff_combination_add_elt (aff_inv, parts.symbol, 1);
> + parts.symbol = NULL_TREE;
> + /* Reset SIMPLE_INV since symbol address needs to be computed
> + outside of address expression in this case. */
> + simple_inv = false;
> + /* Symbol part is moved back to base part, it can't be NULL. */
> + parts.base = integer_one_node;
> }
> - else
> - parts.index = NULL_TREE;
> }
> else
> {
> @@ -4787,6 +4784,7 @@ get_address_cost (struct ivopts_data *data, struct
> iv_use *use,
> neutralize such effects. */
> cost.cost = adjust_setup_cost (data, cost.cost, true);
> cost.scratch = cost.cost;
> + cost.complexity += 1;
> }
>
> cost += var_cost;
> --
> 2.43.0
